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Dear colleagues,<br>
<br>
here is one paper on gravity waves parameterization<br>
I would like to circulate in our stochastic community!<br>
<br>
Best regards,<br>
<br>
Francois Lott<br>
<br>
A stochastic parameterization of non-orographic gravity waves:
Formalism and impact on the equatorial stratosphere<br>
<a
href="http://www.agu.org/journals/gl/gl1206/2012GL051001/index.shtml#sec3"></a>
<div id="content_article"><br>
<p class="author"><a>F. Lott</a>, <a>L. Guez</a>, and <a>P.
Maury</a></p>
</div>
A formalism is proposed to represent a broadband spectrum of Gravity
Waves (GWs) via the superposition of a large ensemble of
statistically independent monochromatic ones. To produce this large
ensemble at a reasonable numerical cost, we use the fact that the
life cycles of the waves needed to be parameterized in General
Circulation Models (GCMs) have time scales that largely exceed the
time step of the model. We can therefore launch few waves with
characteristics chosen randomly at each time step, and make them
having an effect on a longer time scale by applying an AR1 relation
between the gravity waves drag at a given time and that at the next
time step. The stochastic GW parameterization is applied to a GCM in
the tropics, and its additional drag causes a realistic
Quasi-Biennial Oscillation (QBO). The more realistic wind structure
also results in a better representation of the large scale
equatorial waves, like the Rossby Gravity Waves (RGWs) with periods
around 4–5 day.<br>
<br>
<a class="moz-txt-link-freetext" href="http://www.agu.org/journals/gl/gl1206/2012GL051001/">http://www.agu.org/journals/gl/gl1206/2012GL051001/</a><br>
<br>
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